<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>练习题二</title>
</head>

<body>
    <script>
        function he(x, y) {
            let num = x + y
            return num
        }
        let num2 = he(4, 5)
        document.write(`两个数的和为：${num2}`)
    </script>
</body>

</html>